Effect of Binder Modification on the Performance of an Ultrathin
Overlay Pavement Preservation Strategy
Professor Walaa S. Mogawer, P.E., F.ASCEProfessor of Civil & Environmental Engineering
Director - Highway Sustainability Research Center University of Massachusetts Dartmouth!"
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Northeast Asphalt User Producer Group MeetingOctober 22nd, 2015 !"Burlington, VT
Research Team
Name InstituteWalaa S. Mogawer University of MassachusettsAlexander J. Austerman University of MassachusettsShane Underwood Arizona Sate University
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
Overall Study Focus
Asphalt-Rubber (AR) Binder
Warm Mix Asphalt Technology -Wax Based Ultrathin Overlay
(UTOL) Pavement Preservation Strategy
Polymer Modified Asphalt (PMA)
ORWITH &
WITHOUT =
BackgroundØ A common goal of FHWA “Every Day Counts” initiative is to
improve the environmental sustainability of roads.
Ø RIDOT acting on the initiative’s goal by incorporating sustainable and environmentally friendly technologies, GTR and WMA, into engineered asphalt mixtures used for pavement preservation strategies including high performance ultra-thin lift overlays (UTOL).
Ø UTOL have a thickness of one inch or less and are used in applications requiring higher levels of rutting and fatigue cracking resistance.
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
BackgroundØ Agencies in Arizona, Maryland, Michigan, New Jersey, New
York, and Ohio have developed specifications for high performance thin overlays used in pavement preservation.
Ø These specifications normally require the use of Polymer Modified Asphalt (PMA) binder.
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
AR BindersØ A PG58-28 base binder from a local supplier in Massachusetts
was used for development of the AR binder.
Ø The GTR utilized was obtained in mesh sizes of #40 and #80 mesh and used to fabricate the AR binders through a wet process.
Ø GTR dosage was varied for each mesh size in order to obtain a resultant AR binder with properties comparable to the PMA binder.
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
ObjectivesØ Determine if AR binders used in conjunction with and without
WMA will provide similar or better performance as compared to a PMA binder used with and without WMA in a high performance UTOL mixture.
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
Experimental Plan - BinderPG58S-28
Binder
#40 Mesh Rubber
Vary Percentage of Rubber to Obtain Specific PG Grade per AASHTO
M332
Binder Testing
Performance GradeAASHTO M332
Multiple Stress Creep Recovery
(MSCR) TestAASHTO T350
Low Temperature Cracking
Asphalt Binder Cracking Device (ABCD)AASHTO TP92
Polymer Modified Asphalt Binder
PG64E-28
#80 Mesh Rubber
PG64E-28
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
Experimental Plan - Mixture9.5mm UTOL
Pavement Preservation
Strategy Mixture
Mixture Performance Testing
Reflective Cracking
Overlay Test Tex-248-F
Fatigue CrackingAASHTO
T321
Low Temperature Cracking
Thermal Stress Restrained
Specimen Test (TSRST)
AASHTO TP10-93
Moisture SusceptibilityAASHTO T324
- Hamburg Wheel Tracking
Device
No WMA Technology
With WMA Technology
Fatigue Cracking
Push-Pull test in AMPT
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
PMA BinderØ The PMA binder selected for the study was a PG64E-28 which
has been previously utilized by RIDOT for their Paver Placed Elastomeric Surface Treatment (PPEST) preservation mixture.
Ø The PG64E-28 designation confirms the polymer modification of the binder and the “E” designation indicates the binder is suitable for an extremely heavy expected traffic level and loading rate.
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
WMA TechnologyØ The Warm Mix Asphalt technology utilized for this study was
chosen from the Northeast Asphalt User Producer Group (NEAUG) approved list.
Ø An organic based WMA technology known as SonneWarmix was used at a dosage rate of 0.75% by weight of binder.
Ø The mixing and compaction temperature for mixtures using the WMA was reduced approximately 30°F for mixing and 23°F for compaction as compared to the HMA mixtures.
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
AR Binder DevelopmentØ The PMA binder was graded to be a PG64E-28.
Ø By trial and error, AR binders were prepared using each mesh size at varying GTR contents until the grade of the resultant AR binder matched the PMA binder grade of a PG64E-28.
Ø For each mesh size, 15% GTR was required to attain the PG64E-28 grade.
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
Binder Grading Results
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
PG58-28VirginBinder
PMABinder
AR– 15%#40Mesh
AR– 15%#80Mesh
RollingThin-FilmOvenResidue(T240)MultipleStressCreepRecovery(MSCR)TestTemperature,°C 58 64 64 64
Jnr3.2 2.602 0.1586 0.4301 0.4907
LoadingDesignation S E E E
FinalAASHTOM332Grade 58S-28 64E-28 64E-28 64E-28
Binder Low Temperature Cracking Performance
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
Ø The Asphalt Binder Cracking Device (ABCD) was used to determine the low temperature cracking resistance of the PMA and AR binders with and without WMA in accordance with AASHTO TP92-14.
Binder Low Temperature Cracking Performance Results
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
BinderAverageABCD
CrackingTemperature,°C
PMABinder -37.8
ARBinder15%#40Mesh -37.8
ARBinder15%#80Mesh -44.9
PMABinder+WMA -36.0
ARBinder15%#40Mesh+WMA -40.9
ARBinder15%#80Mesh+WMA -44.9
Mixture DesignØ The mixtures were developed using the RIDOT Paver Placed Elastomeric
Surface Treatment (PPEST) specification
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
Sieve Size9.5 mm Mixture
Gradation
9.5 mm PPESTGap-Graded Specification
12.5 mm 100 1009.5 mm 93.0 91-954.75 mm (No. 4) 42.5 40-452.36 mm (No. 8) 24.0 22-261.18 mm (No. 16) 16.0 -0.600 mm (No. 30) 10.5 9-120.300 mm (No. 50) 7.0 6-80.150 mm (No. 100) 5.0 -0.075 mm (No. 200) 4.0 4.0
Binder Content, % 6.75% 6.0% Min.
Rutting/Moisture Susceptibility -Hamburg Wheel Tracking Device (HWTD)
- HWTD testing conducted in accordance with AASHTO T324
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
- Water temperature of 50ºC (122ºF)
- Test duration of 20,000 cycles
Stripping Inflection Point (SIP)
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 20,000
Number of Passes
Rut
Dep
th (
mm
)
Stripping Inflection
Point(SIP)
Number of Passes to Stripping
Inflection Point (SIP)
Number of Passes
Failure, N f
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
HWTD Results
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
PMA AR #80 Mesh AR #40 Mesh
HMA or WMA HMA WMA HMA WMA HMA WMAStripping Inflection Point NONE NONE NONE NONE NONE NONE
Rut Depth at 10,000 Passes (mm)
0.75 3.63 2.18 3.88 1.86 2.39
Rut Depth at 20,000 Passes (mm)
0.97 4.28 2.66 5.22 2.36 3.97
Fatigue – Four Point Flexural Beam
Temperature Strain Level15°C (59°F) 1,000µεTesting in Accordance with
AASHTO T321
- Specimens are fabricated at a target air void level of 7.0 ± 1.0%
- Testing conducted in strain control mode
- Loading Frequency = 10Hz
- Sinusoidal Wave Form
- Failure Criteria = 50% reduction in initial stiffness per AASHTO T321 method
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
Beam Fatigue Test Results
Northeast Asphalt User Producer Group MeetingBurlington, VT! October 22nd, 2015
Cyclic Tension Fatigue Test in the AMPT
Uniaxial Cyclic Tension Fatigue (Pull-Pull)
Temperature Strain Levels (µe)
15°C 250, 500 & 750
Dynamic modulus test ® LVE
Constant cyclic displacement test ®Number of cycles to failure (Nf) based on reduction in phase angle
Analyzed for damage characteristic curve (S-VECD Model)
Simulated fatigue lives using pseudo energy failure criterion
Input to pavement fatigue analysis (not performed in this study)
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
SVECD Results
Northeast Asphalt User Producer Group MeetingBurlington, VT! October 22nd, 2015
Reflective Cracking - Overlay Tester
Diagram from: Zhou et al. “Overlay Tester: Simple Performance Test for Fatigue Cracking” Transportation Research Record: Journal of the Transportation Research Board, No. 2001, Transportation Research Board of the National Academies, Washington, D.C., 2007, pp. 1–8.
- Test Temperature = 15ºC (59ºF)
- Test Termination at 1,200 cycles or 93% Load reduction
- Testing in accordance with Tex-248-F
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
OT Results
Northeast Asphalt User Producer Group MeetingBurlington, VT! October 22nd, 2015
Mixture Low Temperature Cracking -TSRST
- Cooling Rate of -10ºC/hour
- Testing in accordance with AASHTO TP10-93
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
TSRST Results
Northeast Asphalt User Producer Group MeetingBurlington, VT! October 22nd, 2015
ConclusionsØ All mixtures tested provided comparable rutting, moisture
damage, and low temperature cracking performance.
Ø The HMA mixtures with the PMA binder had more resistance to fatigue cracking than the two HMA mixtures with the AR binders according to the beam fatigue test.
Ø The addition of WMA increased the mixture fatigue performance using the PMA binder but decreased beam fatigue performance using the two AR binders.
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
ConclusionsØ The results of the fatigue test using SVECD did not always
agree with the results from the beam fatigue test. In regards to the use of WMA, the only consistent result was that it decreased performance using the AR binders.
Ø The HMA mixture with the PMA binder had a greater resistance to reflective cracking than the HMA mixtures with the two AR binders. The effects of WMA were regarded to be insignificant.
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
AcknowledgementsThe research data and results presented in this paper were part of a study entitled “Using ‘Green’ Technology to Provide a Crack Resistant Thin Overlay for Rhode Island” funded by the Rhode Island Department of Transportation.
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
Thank you!
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
AR BindersØ A PG58-28 base binder from a local supplier in Massachusetts
was used for development of the AR binder.
Ø The GTR utilized was obtained in mesh sizes of #40 and #80 mesh and used to fabricate the AR binders through a wet process.
Ø GTR dosage was varied for each mesh size in order to obtain a resultant AR binder with properties comparable to the PMA binder.
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
AR Binders – Wet ProcessØ The virgin binder was heated to 374ºF (190ºC). Blending was
conducted using a Silverson L4RT-W bench top laboratory high shear mixer at a speed of 5,000 RPM. Blending of the virgin binder and GTR continued for 60 minutes at 374ºF (190ºC).
Ø This process was used to ensure that the complex shear modulus of the binder reached an almost constant value which was considered to be a sign of complete reaction between the rubber particles and the binder.
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
Future WorkØ Concentrate on improving the fatigue and reflective cracking
performance provided by AR binders along with evaluating mixture tests used to measure fatigue cracking performance for these types of high performance UTOL mixtures.
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
ConclusionsØ The two AR binders did not perform as well as the PMA binder
in the high performance UTOL mixture in regards to (1) fatigue cracking as measured by the beam fatigue test and (2) reflective cracking.
Ø Results from the beam fatigue test were not always supported by the fatigue test using SVECD which were variable.
Ø The only detriment to performance provided by WMA was that it decreased fatigue cracking performance using the AR binders.
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015
Experimental MethodologyØ A PMA binder was selected that had shown field success in a
pavement preservation strategy.
Ø AR binders were developed by varying both the percentage and the mesh size of the GTR to determine a combination that provided a similar binder PG as the PMA binder in accordance with AASHTO M332 (MSCR requirements).
Ø This AR binder and the selected PMA binder were then utilized to design the high performance UTOL.
Northeast Asphalt User Producer Group MeetingBurlington, VT¨ October 22nd, 2015